I couldnt believe that less Mass let sink her.

I think it is more likely the Counter Force thats the Water needed to hold the Ship.
@Jan Kyster: Thats why i used the sim.cfg from the Mod. Any Change is restorable.
Edit: Here is the Link of this Mod from Vickers:
http://www.subsim.com/radioroom/down...o=file&id=1433
Hehe, i think he made already some Mods for Destroyer Command.
You can try the normal Mod first, it changes a lot.
Edit2: Asashio Mod DD from peabody:
only changed a little bit, she was better than the Fubuki.
Mass=2365
gc height=the same
fr ratio=0,45
LR=0,55
UD=0,18